why is this else block executed twice?

I have the following code which correctly calculates the jaccard similarity between an input char array and an existing array of char arrays. jacc_sim_rec[] is used to record the similarities which satisfy a minimum threshold value. The for loop is used to iterate through the multidimensional array and the loop is supposed to continue checking similarity if minimum threshold is not satisfied at if (jacc_sim < SIM_THRESHOLD); else record the result at

else
    {
        jacc_sim_rec[j] = jacc_sim;//keep record of similarity
        ++j;//record number of highly similar elements
    }

my problem is, the whole statements in the else block is executed twice every time the threshold value is satisfied.

int j=0;

void calc_jac_sim( char*INCOMING, int grp)
{
    unsigned long i, j11 = 0, j01 = 0, j10 = 0,m=0;
    char *m11, *m01, *m10;
    float jacc_sim = 0.0;
    char r1[SBF_LEN] = { NULL };
    char r2[SBF_LEN] = { NULL };
    char r3[SBF_LEN] = { NULL };
    int cnt = SBF_LEN - 1;

    clear_jacc_sim_info();

    for (int i = 0; i <= SBF_REC[grp]; ++i)
    {
        while (cnt >= 0)
        {
            r1[cnt] = SBF[grp][i][cnt] & INCOMING[cnt];
            r2[cnt] = ~SBF[grp][i][cnt] & INCOMING[cnt];
            r3[cnt] = SBF[grp][i][cnt] & ~INCOMING[cnt];
            cnt--;
        }
        m11 = ( char*)r1;
        m01 = ( char*)r2;
        m10 = ( char*)r3;

        for (m = SBF_LEN * sizeof( char); m--;
             j11 += NumberOfSetBits(*m11++),
                 j01 += NumberOfSetBits(*m01++),
                 j10 += NumberOfSetBits(*m10++));

        jacc_sim = j11 / (float)(j11 + j01 + j10);

        if (jacc_sim < SIM_THRESHOLD);
        //continue;//do nothing
        else
        {
            jacc_sim_rec[j] = jacc_sim;//keep record of similarity
            ++j;//record number of highly similar elements
        }
    }

}